The calculated risk of fatal secondary malignancies from intensity-modulated radiation therapy

Journal Article · Fri Jul 15 04:00:00 EDT 2005 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2005.03.053· OSTI ID:20698631

Kry, Stephen F ^[1]; Salehpour, Mohammad ^[1]; Followill, David S ^[1]; Stovall, Marilyn ^[1]; Kuban, Deborah A ^[2]; White, R Allen ^[3]; Rosen, Isaac I ^[1]

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1. Department of Radiation Physics, Unversity of Texas M.D. Anderson Cancer Center, Houston, TX (United States)
2. Department of Radiation Oncology, Unversity of Texas M.D. Anderson Cancer Center, Houston, TX (United States)
3. Department of Biomathematics, Unversity of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

Purpose: Out-of-field radiation doses to normal tissues may be associated with an increased risk of secondary malignancies, particularly in long-term survivors. Step-and-shoot intensity-modulated radiation therapy (IMRT), an increasingly popular treatment modality, yields higher out-of-field doses than do conventional treatments, because of an increase in required monitor units (beam-on time). Methods: We used published risk coefficients (NRCP Report 116) and out-of-field dose equivalents to multiple organ sites to estimate a conservative maximal risk of fatal secondary malignancy associated with 6 IMRT approaches and 1 conventional external-beam approach for prostate cancer. Results: Depending on treatment energy, the IMRT treatments required 3.5-4.9 times as many monitor units to deliver as did the conventional treatment. The conservative maximum risk of fatal second malignancy was 1.7% for conventional radiation, 2.1% for IMRT using 10-MV X-rays, and 5.1% for IMRT using 18-MV X-rays. Intermediate risks were associated with IMRT using 6-MV X-rays: 2.9% for treatment with the Varian accelerator and 3.7% for treatment with the Siemens accelerator, as well as using 15-MV X-rays: 3.4% (Varian) and 4.0% (Siemens). Conclusion: The risk of fatal secondary malignancy differed substantially between IMRT and conventional radiation therapy for prostate cancer, as well as between different IMRT approaches. Perhaps this risk should be considered when choosing the optimal treatment technique and delivery system for patients who will undergo prostate radiation.

• OSTI ID: 20698631
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 4 Vol. 62; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ACCELERATORS
CARCINOMAS
DOSE EQUIVALENTS
HEALTH HAZARDS
PATIENTS
PROSTATE
RADIATION DOSES
RADIOTHERAPY